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Publication Date
Degree PhD
Discipline/Department Chemistry
Degree Level doctoral
University/Publisher Clemson University
Abstract Conjugated polymer nanoparticles (CPNs) possess important characteristics such as high fluorescence brightness, reasonable photostability, and non-toxicity. These properties allow the use of CPNs in fluorescence based cellular and biological applications including cellular labeling, imaging, biosensing, and single particle tracking. To realize the broad applications of CPNs, it is required that CPNs possess functionality to conjugate a recognition moiety and maintain colloidal stability in biological media. In the following Dissertation, we have prepared functionalized CPNs by surface passivation with head group- functionalized poly (ethylene glycol) lipids and proteins. We studied the colloidal stability of CPNs in biological media and investigated their utility as cellular labels, fluid phase markers and detection reagent in immunoassay. Chapter 1 summarizes the general background information of CPNs including methods of preparation, physical properties, bioanalytical applications, and functionalization strategies. Chapter 2 contains a systematic study of a simple and rapid method to prepare extremely bright, functionalized, stable and biocompatible conjugated polymer nanoparticles incorporating functionalized polyethylene glycol (PEG) lipids by reprecipitation. The size of these nanoparticles, as determined by TEM, was 24±5 nm. These nanoparticles retain the fundamental spectroscopic properties of conjugated polymer nanoparticles prepared without PEG lipids, but demonstrate greater hydrophilicity and quantum yield compared to unmodified conjugated polymer nanoparticles. Nanoparticles were prepared with several PEG lipid functional end groups, including biotin and carboxy moieties that can then be conjugated to biomolecules. We have demonstrated the availability of these end groups for functionalization using the interaction of biotin PEG lipid conjugated polymer nanoparticles with streptavidin. To demonstrate that nanoparticle functionalization could be used for targeted labeling of specific cellular proteins, biotinylated PEG lipid conjugated polymer nanoparticles were bound to biotinylated anti-CD 16/32 antibodies on J774A.1 cell surface receptors, using streptavidin as a linker. This work represents a method of preparation of bright and biocompatible CPNs by inclusion of functionalized PEG lipids. The functional end group on PEG lipid CPNs offers a link to conjugate CPNs to biomolecules. Hence, PEG-lipid CPNs are a viable technology for targeted labeling and imaging in biological systems. Chapter 3 constitutes the comparative study of sensitivity and limit of detection using PEG-lipid functionalized CPNs as a fluid phase marker in J774A.1 cells compared to cells loaded with carboxy-functionalized quantum dots (Q dots) or a dextran-linked small molecule organic dyes (Alexa fluor 488 dextran (AF488-dex)). Under typical conditions used for ex vivo biological imaging or flow cytometry, these CPNs were 175x brighter than Qdots and 1,400x brighter than AF488-dex. Evaluation of the minimum incubation concentration…
Subjects/Keywords Bioanalysis; Conjugated polymer nanoparticles; Detection; Imaging; Sensing; Chemistry
Contributors Dr. Kennth A. Christensen; Dr. Brian Dominy; Dr. Jeffrey Anker; Dr. George Chumanov
Country of Publication us
Record ID oai:tigerprints.clemson.edu:all_dissertations-2303
Repository clemson
Date Retrieved
Date Indexed 2020-05-01

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